Field of the Invention
The present invention relates to a topical pharmaceutical composition containing diacerein and/or its analogs, and also relates to uses of this topical pharmaceutical composition in treatment of various diseases or conditions.
Descriptions of the Related Art
Chemically, rhein is 9, 10-dihydro-4, 5-dihydroxy-9, 10-dioxo-2-anthracene carboxylic acid having a structure of Formula (I), and one of its prodrugs, diacerein, is 4, 5-bis (acetyloxy) 9, 10-dihydro-4, 5-dihydroxy-9, 10-dioxo-2-anthracenecarboxylic acid having a structure of Formula (II). Diacerein is entirely converted into rhein before reaching the systemic circulation, and exerts its physiological function in form of rhein within the body.

Diacerein is an anti-inflammatory agent widely used in the treatment of osteoarthritis, which has been demonstrated to inhibit interleukin-1 (IL-1) signaling. Presently, diacerein capsules are available in 50 mg strength and are marketed under various trade names in different countries, including Art 50®, Artrodar®, etc. As disclosed in U.S. Pat. Nos. 8,536,152 and 8,865,689, diacerein can be used as an adjunctive treatment for type II diabetes mellitus, and was also found to be effective in reducing blood uric acid levels and can accordingly be used for treating hyperuricemia or a metabolic disorder associated with hyperuricemia. In addition, it has been reported that diacerein has a potential effect in the treatment of epidermolysis bullosa (Wally et al., Orphanet Journal of Rare Diseases, 2013, vol. 8, issue 69).
Although diacerein can be administered by the oral route, it cannot be completely absorbed by the digestive tract, and the oral bioavailability of diacerein has been estimated to be approximately 40% to 60%. The incomplete absorption of diacerein may result in undesirable side effects such as diarrhea or soft stools. In vitro and in vivo studies have showed that non-absorbed diacerein is metabolized to rhein in the colon, which then induces a laxative effect.
Since such side effects may occur due to oral administration, non-oral diacerein compositions have been proposed to overcome these problems.
PCT International Application No. WO 2009/133430 discloses topical compositions containing diacerein or rhein, which can be in various forms, such as a lotion, cream, ointment, paste, gel, etc. However, these compositions are not intended for any specific disease, and thus one cannot know which form would be most suitable for a certain kind of disease to be treated from the context of this article.
Wally et al. disclosed a cream diacerein formulation for epidermolysis bullosa (Wally et al., Orphanet Journal of Rare Diseases, 2013, vol. 8, issue 69). However, it is unclear whether or how the properties of the formulation affect the treatment efficacy on epidermolysis bullosa from this article.
It appears that precise properties of diacerein formulations are very important for its treatment efficacy for different diseases.
Considering that the literature provides little information about the relationship between physicochemical properties of a diacerein/rhein topical formulation and its treatment effect, the present invention provides topical formulations adapted to different diseases accordingly.